As we all know, in order to realize the energy-saving purpose, an existing air-conditioning cooling tower has started using a water turbine to drive a cooling fan, thereby fully utilizing energy of circulating water flow of the cooling tower to transform the energy to driving force of the water turbine; and the water turbine is used for transforming water energy to rotation mechanical energy for driving the cooling fan, thereby eliminating a traditional high-power cooling motor and realizing very significant energy-saving effect.
Presently, a circulating water abundant water head of the industrial air-conditioning cooling tower in China is 4 m-15 m, and the pressure water head of 0.5 m-1 m is required in the position for distributing water pipes, so that the water turbine for recovering the part of the circulating water abundant water head works in an environment with back pressure; but the rotational speed of the fan of the cooing tower is lower, in order to realize direct connection with the fan of the cooling tower, the low-speed mixed flow type water turbine must be selected; however, in the current spectrum of the water turbines in China, the low-speed mixed flow type water turbine which can meet the working environment and be directly connected with the cooling fan is still absent, the driving mode of connecting the ordinary mixed flow type water turbine with the fan of the cooling tower through a speed reducer needs to be adopted, as the working conditions of a speed reduction box are poorer, not only the noise is great and the service life is short, but also the manufacturing cost is correspondingly improved. Therefore, the mixed flow type water turbine which can meet the low unit rotational speed under the working environment and be directly connected with the fan of the cooling tower is designed, thereby having great practical significance.